Editors: | F. Kongoli, M. Haumann, P. Wasserscheid, T. Welton, M. Gaune-Escard, A. Angell, A. Riisager |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2018 |
Pages: | 154 pages |
ISBN: | 978-1-987820-86-7 |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
The palladium-catalysed reaction between aryl halides or vinyl halides and alkenes in the presence of a base — referred to as the Heck reaction — facilitates the carbon-carbon coupling with preservation of double bond. Next to the common VOC solvents, ionic liquids (ILs) have shown great potential for Heck reaction under homogeneous conditions.[1,2] However, for the recycling of expensive metal heterogenization, this system becomes a necessity. One of the potential methods includes supporting Pd complexes and an ionic liquid in a form of Supported Ionic Liquid Catalyst (SILCA) while avoiding the use of toxic and expensive ligands.
In a present study, we designed new silica supported catalyst with the nitrogen-rich ionic liquid layer that can ligate active palladium. Through the multiple anchoring points, leaching of the metal was suppressed, and catalyst activity was preserved. Optimization was done by changing the support, metal sources, and varying anion-cation parts of ILs. Remarkable activity in different Heck reactions was demonstrated. In order to get a full understanding of the catalyst structure and behaviour, it was characterised by means of nitrogen physisorption, TGA, XRD, FT-IR, solid-state NMR, XPS, SEM and ICP-MS.